Archive for category Space and astronomy

One thing The Mail normally does quite well are giant picture spreads – stories with lots of giant photos and maybe a couple of hundred words of text to explain them. Normally…

Am I being pedantic? I don’t care; the “spiralling meteors” are not meteors, they’re stars! As the Earth turns, the stars seem to rotate around the Pole Star (the “stationary” speck of light in the centre of the image), and if you take a long exposure photograph of them they seem to draw circles in the sky. Now, there are meteors in this image but they are not spiralling and they are, err, a bit tricky to see, especially since The Mail has squished the images down to web resolution.

Edit: After I’ve complained about the Mail squashing the image too much, WordPress has gone and squashed it even further. Click on the images to view them unsquashed.

Can you see them? They’re more visible in the full size version, and they do not spiral. In fact, that’s how you tell a meteor from a star – the meteor moves so quickly that the rotation of the Earth has no effect on its apparent path, so it blazes in a straight line across the sky. All in all, this is a great star trail picture, but it’s not the best meteor picture ever, and the way The Mail has presented it means it’s not a meteor picture at all.

The bright moon made watching/capturing difficult this year and the very wide angle shot makes for a good composition but lesser meteor detail.

Incidentally, there are a lot of really good photos on Humpage’s website – not just of stars and satellites, but hurricanes, icebergs and aurorae too – and, unlike The Mail, he knows the difference between a star and a meteor. Enjoy!

Neptune’s birthday is today, not tomorrow! We’ll all be celebrating on the wrong day!

Never mind phone hacking, this is the realscandal.

Edit: The BBC is even more wrong, claiming Neptune’s birthday is July 12. The philistines!

Double edit: In fact, it looks like we’re all right! July 10 is one average Neptunian year after the date of discovery, July 11 is the day when Neptune will have made precisely one orbit around the solar system’s barycentre (i.e., its centre of mass when you take the Sun and all the planets into account), and July 12 is the day that Neptune will have made precisely one orbit around the Sun. (A figure of July 13 is floating around as well, most likely as a result of an Indian newspaper article which has taken timezones into account). Thanks to Up, Blogstronomy and the Wikipedia users on Talk:Neptune!

Edit: After a quick email conversation with the author, the article has now been rewritten (direct link). Although it still has a slightly cringeworthy headline, it no longer contains misunderstandings about the paper and is all in all pretty good! I’ve hidden the original post behind the cut.

The road I live on has a railway running across the end of it. Every day, hundreds of tons of metal speeds along the line just a hundred metres or so from my house. Yet I don’t live in fear of waking up one morning and finding a train’s crashed into my house, because of course the trains are restricted to the railway tracks.

Space is much the same. Asteroids are whizzing around over our heads every day, but they follow precisely defined orbits through the sky. An asteroid passing close to the Earth is no more a “near miss” than a train passing my house without hitting it is a “lucky escape”.

Incidentally, the claim that it’s “as powerful as 15 atomic bombs” doesn’t come from any scientific authority. It comes from the news.com.au journalist – who doesn’t appear to be a science journalist at all, but a technology journalist – digging up an old New Scientist article about an asteroid that exploded with the energy of three nuclear bombs (three of the very small Hiroshima bombs, I should point out, not a modern nuclear bomb), and then scaling it up. This is a stupid calculation for a number of reasons:

You can’t just say “this asteroid is 10 metres long, this asteroid is 50 metres long, therefore it’s 5 times bigger”. It’s the volume which is important – the length times the width times the height. Assuming the asteroid is 5 times bigger in each direction, then it’s 5 x 5 x 5 times bigger, which is 125 times the size. If the journalist hadn’t cocked up his maths, he could have made this asteroid sound EVEN SCARIER. Except…

The amount of energy an asteroid has depends on its speed. A fast moving asteroid carries far more energy than a slow moving one, and a small increase in speed causes a much larger increase in energy.** The gravitational pull of the Earth as the asteroid approaches plays a large role in determining its speed, so the energy it would have would depend on the route it took to Earth. Since this asteroid is not heading for Earth, it’s meaningless to ask how much energy it would have if it hit Earth.

It also depends what the asteroid is made of. Most asteroids are made of dust and ice, and burn up harmlessly in the atmosphere. A few – maybe one per year – explode high up in the atmosphere. And a very, very few – mostly large metallic asteroids that don’t burn as well – hit the ground. Again, we don’t know what this asteroid is made of.

THE ASTEROID IS TWO MILLION MILES AWAY AND WILL NOT HIT EARTH AT ANY TIME IN THE FORESEEABLE FUTURE.

At any rate, there are literally thousands of asteroids this big – or indeed much bigger – rattling around near-Earth space, and there must be thousands more we haven’t detected yet. It’s worth being sensibly worried about the risk of currently undiscovered asteroid hitting us, but getting worked up about an asteroid that we know can’t hit us is just stupid.

Now, if you’ll excuse me, I’m off to dig a train-proof bunker in my garden.

* Psst, Daily Mail Reporter. “Earth” has a capital “e”.

** In fact, energy is proportional to speed squared – if you double your speed, your energy goes up fourfold.

This will be the last “supermoon” post, I hope. There’s just something about it which seems to make journalists become especially stupid. Perhaps the Victorian doctors who said the moon caused “lunacy” were onto something.

Anyway, here’s what has pride of place on the Mail‘s science page today:

You know, lunar planet! That… moony planet?

Okay, Daily Mail Reporter, find your nearest 8 year old relative and ask them what the difference is between a “planet” and a “moon“. The answer may (not) surprise you!

The photos in the article are very nice looking, but the reason the moon looks so giant in them isn’t because of the “supermoon”. The trick is to take the photos of the moon when it’s very low on the horizon, grazing very distant buildings. Using a powerful zoom lens, you zoom in on the distant buildings, so they look normal sized and the moon looks gigantic. This isn’t something unique to supermoons, it can be done any day.

Like I said in last week’s post, the “supermoon” would never be as dramatic as the papers claimed – it was only 6% larger than usual, and this happens twice a month. Without a decent telescope and a camera, you probably wouldn’t notice the “supermoon” at all.

Normally, scientists are meant to be circumspect and reserved about cause and effect. We’re supposed to deal in probabilities, statistics and uncertainties. However, on this occasion, I have absolutely no qualms in saying this: The Daily Mail is wrong. The “Supermoon” had nothing to do with the terrible earthquake off the coast of Japan today.

Ben Goldacre and Phil Plait have already produced some admirable rebuttals to the Mail‘s exploitative scaremongering; these are my thoughts, but I recommend reading the linked posts.

The powerful tsunami that today slammed into Japan’s eastern coast comes just two days after warnings that the movement of the moon could trigger unpredictable events on Earth.

Except none of these “warnings” come from scientists. The only people who took the “Supermoon” seriously were internet conspiracy theorists and the tabloids. And…

Astrologers predicted that on March 19 – a week tomorrow – the so-called ‘supermoon’ will be closer to Earth than at any time since 1992, just 221,567 miles away, and that its gravitational pull will bring chaos to Earth.

An astrologer is the not same thing as an astronomer. A warning from an astronomer should (generally) be taken seriously. A warning from an astrologer isn’t worth the paper it’s printed on.

Others on the Internet have predicted it will cause further catastrophes such as volcanic eruptions and earthquakes.

“Others on the Internet”? Of course, everything that was ever written on the internet MUST be true.*

* Fully aware of the hypocrisy, thank you very much.

However the ‘supermoon’ date is still eight days away. But those that adhere to this particular belief could claim that this was still close enough for there to be some kind of effect.

Ok, as everyone knows, the moon orbits once a month. Once every two weeks, it comes close to the Earth – this is the “perigee” of its orbit – and in between these perigees we have the furthest points: the “apogee”. This means that eight days before the perigee, it will be as far away as possible from the Earth; the exact opposite of a “supermoon”. Its gravity would be weaker, not stronger.

The energy needed to produce an earthquake builds slowly through stress and strain in the rocks where tectonic plates meet, over years or decades. A tiny change in the position of the moon – a change which, remember, happens twice a month – will have virtually no effect compared the constant force of billions of tons of rock pressing against each other.

Two days ago, in an interview with ABC radio discussing the potential impact of the March 19 supermoon, astrologer Richard Nolle, who first coined the term in 1979, said he was convinced that lunar perigees cause natural disasters on Earth.

‘Supermoons have a historical association with strong storms, very high tides, extreme tides and also earthquakes,’ he said.

The only one of those that is true is that “Supermoons” can cause high tides (and even then, it only changes the tidal range by a couple of percent). There is no association between “Supermoons” and storms or major earthquakes. And again, an astrologer is NOT an astronomer.

Natural disasters are unfortunately common. Earthquakes, storms and floods happen with depressing regularity – look hard enough and you can find disasters happening around any supermoon. What’s important is to the look at the disasters that weren’t linked to a supermoon. No scientific study has shown an increase in quakes or storms around supermoons.

What do the actual scientists say?

Dr David Harland, space historian and author, said: ‘It’s possible that the moon may be a kilometre or two closer to Earth than normal at a perigee, but it’s an utterly insignificant event.’

Professor George Helffrich, a seismologist at the University of Bristol was equally dismissive.

‘Complete nonsense. The moon has no significant effect on earthquake triggering.

‘If the moon triggers “big” earthquakes, it would trigger the many of millions of times more “small” earthquakes that happen daily. There is no time dependence of those; hence no moon effect.’

[…]

John S Whalley, geoscience programme manager at the University of Portsmouth, agreed there was no correlation.

‘There is no established correlation between variations in the orbit of the moon and either the number or magnitude of earthquakes.

‘It is all too easy, with hindsight, to link major earthquakes to variations in all sort of parameters.

‘The real test is to look at the vast numbers of earthquakes of all magnitudes that occur on a daily basis worldwide.

‘Any correlation with the lunar orbit would have to be established on the basis of this population of earthquakes, not on individual high magnitude events. In need hardly add that no such correlation has been established.’

I would end this post with another glib link to the SMBC comic, but frankly I don’t feel like this the right time for daft jokes. Nor is it the appropriate time for a newspaper with a readership of millions to be giving a platform to charlatans and conspiracy theorists, who seize on a terrible tragedy just to get a little bit of publicity for their pseudoscientific claims.